The objectives of the proposed research are to: 1) assess the differential sensitivity to sedative and anxiolytic drugs based on age, sex, hormonal status and Central Nervous System tolerance, 2) elucidate the complex relationship between pharmacokinetics and pharmacodynamics taking into consideration the above factors as well as the rapidity of drug rise time and lipid solubility of the drug, 3) continue to examine the components of acute tolerance including the recovery from the early peak effect and later rapid recovery period, 4) examine the relationship of chronic tolerance to the components of acute tolerance, and 5) continue to develop a simple performance task battery in which drug induced impairment correlates well with that of drug induced impairment of driving related skills and simulated skills. The development of these simple performance tasks not requiring sustained motivation or learning may allow for performance impairment alone or in combination with drug blood levels of provide for a more accurate assessment of actual or potential driving impairment than with blood levels alone. In a clinical setting, such tests could be utilized prognostically to assess patient impairment secondary to prescription drugs.